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Thermodynamic data evaluation for chemical RIB purification - the experimentalists approach

This study explores the thermodynamic data evaluation for the purification of chemical RIBs, focusing on the experimentalist's approach. It discusses adsorption interactions, boundary conditions, chemical separation, and volatility and adsorption properties. Various elements and compounds are analyzed, along with their surface methods and bonding characteristics.

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Thermodynamic data evaluation for chemical RIB purification - the experimentalists approach

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  1. Thermodynamic data evaluation for chemical RIB purification - the experimentalists approach R. Eichler1,2,*, J. Neuhausen1 1Laboratory for Radio- and Environmental Chemistry, Paul Scherrer Institute Villigen, CH-5232, Switzerland 2Department for Chemistry and Biochemistry, University Bern, CH-3012, Switzerland

  2. Outline • 1. Introduction • Adsorption interactions: • A) Covalent coordinative bond • B) Dispersion interaction • C) Metal bond • 3. Summary

  3. Boundary conditions - needs Transactinide chemistry? Chemical RIB Purification • * Simple volatile species (element or compound) • * Formation and release properties – • Thermodynamics and Kinetics • * Source design – materials – • Reaction and Adsorption • * Chemical separation – • Volatility and Adsorption

  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 H He F B C N O Li Be Ne Cl Al Si P S Na Mg Ar Br Ga Ge As Se K Ca Sc V Fe Co Cu Kr Ti Cr Ni Zn I Sn Sb Te Cd Rb Sr Nb Ru Rh Xe Zr Mo Pd Ag In Y Tl Pb Po At Hg Cs Ba La* Ta Os Ir Rn Hf W Pt Au Bi Hs Ds Rg Mt Db Rf Bh Sg 116 115 Fr Ra Ac** 112 114 113 Mn Tb Ce Pr Nd Pm Sm Eu Gd Dy Ho Er Tm Yb Lu * ** Tc Bk Th Pa U Np Pu Am Cm Cf Es Fm Md No Lr Re Gas phase Chemistry of transactinides elements compounds

  5. yield T Isothermal gas chromatography External chromatogram T=300K Detector 50% T=600K T50 Result:T50 DHads

  6. T yield length Thermochromatography Temperature gradient T=300K T=100K Internal chromatogram Tdep detectors Volatility wanted! Result:Tdep DHads

  7. Frenkel-type adsorption kinetics: • a= 1/no*exp(-DHads/RT) • phonon frequency of the surface • material : no • -> sticking probability if needed gas transport through tubes: laminar flow DHads for short-lived isotopes radioactive decay: t1/2 else: texp diffusion in the carrier gas Gilliland eqn. Kinetic model of gas adsorption chromatography Monte Carlo Simulation Condition : * Simple reversible single step adsorption process i.e. No change of the chemical state during the process and no irreversible reaction with the surface or diffusion into the surface * zero surface coverage / carrier free amounts = single atoms no phonon frequency Zvara, I., Radiochim. Acta 38, 95 (1985).

  8. Mn Tc Re Gas phase Chemistry of Transactinides 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 H He F B C N O Li Be Ne Cl Al Si P S Na Mg Ar Br Ga Ge As Se K Ca Sc V Fe Co Cu Kr Ti Cr Ni Zn I Sn Sb Te Cd Rb Sr Nb Ru Rh Xe Zr Mo Pd Ag In Y Tl Pb Po At Hg Cs Ba La* Ta Os Ir Rn Hf W Pt Au Bi Hs Ds Rg Mt Db Rf Bh Sg 116 115 Fr Ra Ac** 112 114 113 118 Tb Ce Pr Nd Pm Sm Eu Gd Dy Ho Er Tm Yb Lu * ** Bk Th Pa U Np Pu Am Cm Cf Es Fm Md No Lr Element Compound Surface Method RfRfOX2, RfX4 quartz TC,IC DbDbOX3, DbX5quartzTC,IC SgSgO2X2quartz TC,IC BhBhOCl3quartz IC Hs HsO4quartz TC 112-118 Hg/Pb/Bi/Po/At/Rngold/quartz TC, IC

  9. Adsorption interactions E Chemisorption -DHads > 30 kJ/mol Physisorption DHads< 30 kJ/mol EA EDB Eads re re r A) Covalent coordinative bond C) Metal bond B) Dispersion interaction

  10. Mn Tc Re Gas phase Chemistry of Transactinides 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 H He F B C N O Li Be Ne Cl Al Si P S Na Mg Ar Br Ga Ge As Se K Ca Sc V Fe Co Cu Kr Ti Cr Ni Zn I Sn Sb Te Cd Rb Sr Nb Ru Rh Xe Zr Mo Pd Ag In Y Tl Pb Po At Hg Cs Ba La* Ta Os Ir Rn Hf W Pt Au Bi Hs Ds Rg Mt Db Rf Bh Sg 116 115 Fr Ra Ac** 112 114 113 118 Tb Ce Pr Nd Pm Sm Eu Gd Dy Ho Er Tm Yb Lu * ** Bk Th Pa U Np Pu Am Cm Cf Es Fm Md No Lr Bond Character Chemisorption Chemisorption Chemisorption Chemisorption Physisorption Chemisorption/ Physisorption Element Compound Surface Method RfRfOX2, RfX4 quartz TC,IC DbDbOX3, DbX5quartzTC,IC SgSgO2X2quartz TC,IC BhBhOCl3quartz IC Hs HsO4quartz TC 112-118 Hg/Pb/Bi/Po/At/Rngold/quartz TC,IC

  11. A) Covalent coordinative bond transition element compounds in highest oxidation states -DH0(s) s -DH0(g) DHsubl g 5th period 6th period 7th period -DH0(g), monoatomic metal gases

  12. A) Covalent coordinative bond Db Ta Rf Hf Zr Nb Sg W Mo Bh Hs Re Tc Os Ru

  13. A) Covalent coordinative bond DbOCl3 SgO2Cl2 RfCl4 BhO3Cl quartz surface Eichler, B. et al.: J. Phys. Chem. A 103(46), 9296 (1999).

  14. A) Covalent coordinative bond quartz surface HsO4 Eichler, R. et al.: Radiochim. Acta 87, 151 (1999).

  15. B) Dispersion interaction Inert atoms on metal surfaces: Atoms/molecules on dielectric surfaces: EA/B … effective excitation energy  EA/B = 1.57 . IPA/B*; g = 1 for metals; a … polarizability of the adsorbate; IPA/B … ionisation potentials; re … distance between the adsorbate to the substrate; e … dielectric constant of surface material *Pauling, L. Science1961, 134 (3471), 15.

  16. B) Dispersion interaction re = 240pm (van der Waals radius of Rn)

  17. B) Dispersion interaction  DHMads(Z) / DHMads(Xe) = C(Z,Xe) Z Ne Ar Kr Xe C(Z,Xe) 0.17 0.52 0.72 1 Adhesion model • Description of DHads proportional to the enthalpy of adhesion: • Dgad(A,B) = -2 F (g0(A) g0(B))1/2 • ... dissimilarity parameter (calculated) g0... surface energy at T=0 K F ... geometrical factor (empirically 0.31) VA ... Volume of the spherical adsorbate atom DHads= 0.71*109 F F VA2/3 (g0(A) g0(B))1/2 A.R. Miedema, B.E. Nieuwenhuys Surf. Sci. 104, 491-509 (1981).

  18. B) Dispersion interaction Adhesion model extended Haettig, C. J. Phys. Chem. A 1996, 100 (15), 6243. Nicklass, A.J. Chem. Phys.1995, 102 (22), 8942.

  19. B) Dispersion interaction

  20. B) Dispersion interaction Seth, M.,Schwerdtfeger, P.: J. Chem. Phys. 1997, 106 (9), 3623. Eliav, E. et al. Phys. Rev. A 1995, 52 (4), 2765. R. Eichler, J. Phys. Chem B. 106, 5413 (2004).

  21. C) Metal bond (DHo298(g)-0.5*DHodiss)/DHo298(g) Metallic character dimer formation (non metals)  lattice formation (metals) Eichler, B.: Kernenergie 19, 307 (1976).

  22. C) Metal bond Enthalpy diagram of Release and Adsorption Processes (Elements on Metals) Experiment Hads=HN+HD HV=-Hsolv-HD IN ON

  23. A criterion DHsol> 50 kJ/mol B B B B B B B B A B B B B DHnettoads solid state  adsorbed state B B B B criterion DHsol< 50 kJ/mol C) Metal bond: Eichler/Miedema model: Adsorption Eichler, B., Rossbach, H.: Radiochim. Acta 33, 121 (1983)

  24. C) Metal bond Miedema model: Intermetallic solid solution at infinite dilution B B B B A A B B B B Semi empirical model adjusted to hundreds of binary systems VA... atomic volume VAsol… atomic volume in solution nWS… electron density at Wigner Seitz cell boundaries F… electronegativities (Miedema scale) Rm… hybridization term (empirical, combination dependent) A.R. Miedema, J. Less-Comm. Met. 46, 67 (1975)

  25. r12= c + a ln(A) + bSo(s) V = (4/3 ) pr123 / R* C) Metal bond nWS … electron density at Wigner Seitz cell boundaries Theoretical: Self consistent electronic structure calculations Experimental: nws [d.u.] = 10-2(B/V)1/2 B = bulk modulus V = molar volume [cm3/mole] Empirical: nWS = 0.107955 * A1/2 * (r12/V) * exp (7.03 – (So(s)/ (3*R))) Eichler, B., Rossbach, H.: Radiochim. Acta 33, 121 (1983) Eichler B.: PSI Report 03-01; Villigen (2002), ISSN 1019-0643.

  26. C) Metal bond Derivation of Miedema Electronegativity Parameters • From various electronegativity scales: • Allred-Rochow • Pauling • Allen • Pearson • Sanderson

  27. C) Metal bond Noble gases, halogens excluded “0”

  28. C) Metal bond Noble gases, halogens excluded “0”

  29. C) Metal bond Korrelation –DHads(Au) withDHsubl DHnettoads<50kJ/mol

  30. B+C) Metal bond + Dispersion interaction R. Eichler Radiochim. Acta 93, 245–248 (2005)

  31. Release Enthalpy DHf =DHSubl - DHSol

  32. Release Enthalpy

  33. Off-line Release studies

  34. C) Metal bond Experiment/Eichler-Miedema Empirically or tables Born-Haber cycle Eichler-Miedema

  35. A/B) coordinative / physisorption Elements on quartz Soverna, S., PhD-thesis, University Bern, Bern (2004).

  36. Hot Targets Intermetallic compounds with Rh [1] B. Eichler, PSI Report 03-01, Villigen, 2003

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